The present invention relates to an organopolysiloxane-grafted polysaccharide compound or, more particularly, to a novel and efficient method for the preparation of an organopolysiloxane-grafted polysaccharide compound such as a cellulose derivative substituted by a grafting moiety of an organopolysiloxane, which is useful as an additive ingredient in various kinds of cosmetic and toiletry preparations.
It is known in the prior art that organopolysiloxane-grafted polysaccharide compounds have usefulness not only as a film-forming additive ingredient in hair-care and skin-care toiletry and cosmetic preparations but also as a material of a membrane for gas separation, back-coating agent on thermographic printing paper sheets and an additive in coating compositions such as paints.
Several different methods are proposed for the preparation of an organopolysiloxane-grafted polysaccharide compound in, for example, Japanese Patent Publications 64-8001 and 64-11202, Japanese Patents 071051 and 071084 and Japanese Patent Kokai 7-70204 and 9-136901. These prior art methods, however, are economically not quite satisfactory as an industrial process because of the low efficiency of the reaction between a polysaccharide derivative and an organopolysiloxane as the polymeric reactants pertaining to the grafting reaction even by the use of a catalyst due to the so large difference in the nature of the respective reactants necessarily resulting in a low yield of the desired graft polymer product which contains an unduly large amount of the unreacted reactants. More disadvantageously, the reaction product containing the unreacted reactants and the catalyst compound as such usually cannot be used as an additive ingredient in a cosmetic or toiletry preparation unless the unreacted matters and the catalyst compound are removed in a very complicated and hence expensive purification procedure involving thorough washing of the reaction product with an organic solvent, recovering and recycling of the organic solvent and drying of the reaction product.